Sem
Sem is an MCP server that adds developer tools to AI assistants such as Claude Desktop, Claude Code and Cursor. Entity-level code intelligence: semantic diff, impact analysis, blame, and context for AI agents. It has 3,397 GitHub stars, is released under the Apache-2.0 license and runs locally with npx -y @ataraxy-labs/sem.
- Official
- Developer tools
- Apache-2.0
- Actively maintained
Install Sem
Generated from the server's MCP registry entry. Replace your-value with your own values.
Claude Desktop
{
"mcpServers": {
"sem": {
"command": "npx",
"args": [
"-y",
"@ataraxy-labs/sem"
]
}
}
}Settings > Developer > Edit Config. macOS: ~/Library/Application Support/Claude/, Windows: %APPDATA%\Claude\. Restart Claude Desktop afterwards.
Claude Code
claude mcp add --transport stdio sem -- npx -y @ataraxy-labs/semCursor
{
"mcpServers": {
"sem": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"@ataraxy-labs/sem"
]
}
}
}Project file; use ~/.cursor/mcp.json to enable it in every project.
VS Code
{
"servers": {
"sem": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"@ataraxy-labs/sem"
]
}
}
}Config formats checked against the official docs on Oct 7, 2026: modelcontextprotocol.io (opens in a new tab), code.claude.com (opens in a new tab), cursor.com (opens in a new tab), code.visualstudio.com (opens in a new tab).
About Sem
Part of the Ataraxy Labs stack: agent-native infrastructure for software development. See also: weave (entity-level git merge driver) · inspect (semantic code review) · opensessions (tmux sidebar for coding agents). Read the manifesto: · Essays: · LLMs:
- ai-agents
- developer-tools
- git
- semantic-diff
- tree-sitter
- code-intelligence
- coding-agents
- llm-tools
- typescript
- version-control
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What is Sem?
Sem is an MCP server that adds developer tools to AI assistants such as Claude Desktop, Claude Code and Cursor. Entity-level code intelligence: semantic diff, impact analysis, blame, and context for AI agents. It has 3,397 GitHub stars, is released under the Apache-2.0 license and runs locally with npx -y @ataraxy-labs/sem. The source code is at github.com/Ataraxy-Labs/sem.
How do I install the Sem MCP server?
Add the command npx -y @ataraxy-labs/sem to your MCP client: put it in claude_desktop_config.json for Claude Desktop, run claude mcp add for Claude Code, or add it to .cursor/mcp.json (Cursor) or .vscode/mcp.json (VS Code). The snippets on this page are ready to paste.
Is Sem free?
The server is open source under the Apache-2.0 license, so running it is free. It does not declare any required API key.
Is Sem actively maintained?
The most recent commit was on Oct 7, 2026. The latest release is v0.27.0, published Oct 4, 2026. appsgit only lists MCP servers with a commit in the last six months and re-checks every server daily.